This invention relates to an apparatus and method for remotely repairing existing underground pipe junctions from the inside-out, as opposed to digging a trench and replacing or repairing the pipe from the outside-in. More specifically the present invention relates to a flexible patch used in the repair of an underground pipe junction.
Sewer lines, water lines and other types of buried pipelines can develop leaks over time. These leaks are a result of decaying materials such as the clay used in the construction of the pipeline, obstructions which may clog a line, chemical exposure or crushing due to overburden pressure due to the inferior materials used in very old pipelines. Many older lines require repair to prevent exterior leaking and possible ground water contamination. Additionally, without proper repair ground water can infiltrate into the broken sewer lines, thus causing significant increase in the volume of throughput and the expense of chemicals and other materials used for treatment of the sewer water.
Repairing leaking sewer lines and other forms of fluid transmission lines is very expensive due to the previous necessity of digging a trench from the surface to physically remove the pipe. The removal and replacement of this pipe from the surface is time-consuming, expensive and not practical in many old commercial and residential neighborhoods due to narrow alleyways, heavy traffic and the volume of pipe located below existing buildings or other obstructions.
Thus, xe2x80x9ctrenchless technologyxe2x80x9d was developed which utilizes machinery and methods of repairing sewer pipe and other buried transmission lines from the inside-out. This process eliminates the need for digging expensive trenches aboveground. In brief, the existing main pipeline is repaired by installing a plastic liner which is inserted into the existing pipeline. The plastic liner is then bonded to the internal surface of the existing pipeline by heating or other methods. The existing lateral service lines which feed the main pipeline are then located by the use of a robotic device with an optical camera. Once identified, a hole is drilled by the robot mechanism into the existing pipeline, thus providing access into the lateral service line.
Unfortunately, the hole drilled into the existing lateral service line does not provide a satisfactory seal, thus permitting significant volumes of groundwater, as well as plant roots, dirt and other foreign objects to infiltrate the main pipeline at the junction point between the lateral service line(s) and the main pipeline. Additionally, contaminants within the main pipeline can potentially leak and pollute the adjacent groundwater. As a further complication, some of the lateral service lines are not joined with the main pipeline at a substantially ninety-degree angle but are joined to the pipeline at acute or obtuse angles.
Thus, a need exists to provide a reliable patching mechanism to seal the junction point between the lateral service line and main pipeline which can be operated remotely and which functions from within the small internal confines of the main pipeline.
Others have attempted to seal the junction between the main pipeline and lateral service line, but known approaches have considerable disadvantages. U.S. Pat. No. 5,329,063 to Endoh exemplifies a technique where a flexible tubular liner is inserted into a lateral line so that the entire lateral line receives a lining. Air or liquid pressure is needed to insert the reversed flexible liner into the lateral. Once the liner is extended by the air pressure from the junction to the other end of the lateral pipe, access to that other end of the lateral line is required to cut away any excess liner. In this way, the entire lateral pipe is lined from one end to the other.
As those skilled in the art can appreciate, installing a flexible liner in a lateral service line is very time consuming and difficult. The apparatus required for installation has many moving parts and is complex to operate. Additionally, access to the distal end of the lateral line (i.e., the end away from the main pipeline) is needed to cut away the excess liner. The complex setup required makes sealing the junction of the main pipeline and lateral service line both time consuming and expensive.
Further, the results achieved by the flexible liners are erratic because the lateral service line is not a controlled environment. For example, the lateral may contain debris which will obstruct the flexible liner so that when the liner is hardened, the obstructions will permanently interfere with the flow in the lateral line. Additionally, the environment in into which the flexible liner must be installed is subject to wide temperature swings which further encumbers achieving consistent results. Therefore, there is a need for quickly and inexpensively sealing the junction between a main pipeline and lateral service line with consistent results. This is especially needed in situations where it is difficult or impractical to obtain access to the distal end of a lateral service line. Further, there is a need for quickly curing the epoxy, glue or resins which are used as a sealing medium between the underground patch and the lateral pipeline and main pipeline.
Lateral service lines are also brought into and out of service at different junctures dependent upon the needs of the community. Thus, a need exists for a removable yet effective seal to seal off a lateral service line to remove the line from service.
Additional attempts have additionally been attempted using rigid patch assemblies such as described in U.S. Pat. Nos. 6,082,411 and 6,206,049 to Ward, which are incorporated herein by reference in their entirety. The patching mechanism described in these patents although generally effective, has been found to have limitations since the patch mechanism is not capable of bending to such a degree to allow a proper seal between lateral lines and main lines which are not interconnected at substantially right angles.
Thus, there is a need for an apparatus and method for installing a flexible patching mechanism between a lateral and main pipeline which is sufficiently adaptable to permit defraction and movement as necessary.
It is thus one object of the present invention to provide an apparatus and method for sealing the junction point between a lateral service line and a main pipeline from the inside-out, i.e., using trenchless technology. Thus, in one aspect of the present invention a patching apparatus is provided which may be positioned and installed with a robotic device within a main pipeline. The patching apparatus in one embodiment is comprised of a polyvinyl chloride (PVC) material, or the like, having a flange which is shaped to fit the internal diameter of the main pipeline and an extending stem which penetrates into the lateral service line.
In another aspect of the present invention, the patching apparatus flange contains an interconnection substrate such as felt, sponge or another similar material to provide a resilient, compressible material suitable for sealing the pipe junction. The interconnection substrate may be impregnated with a bonding agent such as a water activated epoxy or grout which sealingly interconnects the patch to the main pipeline and lateral service line. Alternatively, an adhesive, glue, or other type of material may be applied to the interconnector substrate just prior to installation. To further provide sealing in another embodiment, an annular gasket may be positioned around the stem portion to promote sealing engagement between the stem and the internal surface of the lateral service line. The seal provided by the inverted-tee patch effectively eliminates most water intrusion or the influx of plant roots and other matter at the junction point which can seriously damage or obstruct the main pipeline.
It is yet another object of the invention to provide a remotely controlled robotic arm capable of applying the inverted-tee patch to the junction between the main pipeline and lateral service line from within the main pipeline. The robotic arm includes a support cage which holds the inverted-tee patch in place during insertion. The robotic arm laterally extends to apply the patch to the junction. Thus, in yet another aspect of the present invention a robotic arm is interconnected to a substantially elongated robot capable of traveling within a main sewer or other transmission line. The elongated robot is generally positioned by means of a remotely controlled assembly with an optical camera mechanism which properly identifies the junction point of the main pipeline and lateral service line.
It is yet another object of the present invention to provide a flexible patch which does not require curing or the application of pressure to install the patch at the junction between the lateral service line and the main pipeline. Thus, the possibility of error is reduced since the patch is deforms itself to the form of the juncture of the service line and the pipeline and as such is not susceptible to failure as a result of non-controllable environmental factors such as debris in the pipeline, cold temperatures, etc. Furthermore, this type of patch does not require an entire service line to be lined, but only the junction point. Thus, significant time and expense can be saved while achieving a greater degree of reliability.
It is another aspect of the present invention to provide a heating apparatus which can be positioned below the patch mechanism, to accelerate the curing of the glue/epoxy bonding agent which is positioned between the patch and main pipeline. In one embodiment the heating element may be an integral part of the support cage, or alternatively be a separate component which is positioned below, or adjacent the existing support cage. To activate the heating element, a remote control power source may be used to selectively provide electrical heat energy to the heating mechanism for a predetermined period of time. Alternatively, a battery operated mechanism may be used which has a timer which automatically activates and provides heat energy to the patch after a predetermined time period or upon activation of the scissor multiplier to place the patch in its final position of use. Alternatively, different types of energy sources can be used to quickly cure the glue, epoxy or other type of adhesive, including ultra-violet light energy, radiation, or other energy sources commonly known in the art.
It is yet another aspect of the present invention to provide a patching mechanism which allows sufficient deflection between a flange portion and a stem portion to provide improved sealing characteristics at a junction between a lateral line and a main line which is not oriented at a substantially 90xc2x0 or right angle. Thus, in one embodiment of the present invention, a xe2x80x9cflex-jointxe2x80x9d is provided between the flange and the stem, and which allows a deflection angle of at least about five degrees, or a deflector at the lower portion of the stem of at least about 3 inches.
In an alternative embodiment of the present invention the flange is additionally comprised of a flexible material such as PVC pipe or rubber and which further is adapted for conforming to junctions between two pieces of pipe which are not at substantially 90xc2x0 or right angles.
In yet another aspect of the present invention, a seal which can be fit into the stem of the patch or can fit over the stem of the patch is provided. The seal is hydrophilic to prevent any residual water, sludge or other resident of the lateral service line from entering the main pipeline.
Thus, in one aspect of the invention, the following method is provided for installing a pipeline patch:
A method for remotely installing a patch to an underground junction between a main pipeline and a lateral service line, wherein said lateral service line is joined to the main pipeline at an angle other than a ninety-degree angle, comprising the steps of:
(a) providing a patch comprising:
a tubular stem having a substantially rigid portion, a flexible portion, a first end and a second end, the second end having a substantially open aperture for communication with the lateral service line;
a convex flange having an exterior service, an interior surface and a cutout portion operatively sized and interconnected to the first end of said tubular stem, wherein said tubular stem extends away from the exterior surface of said convex flange;
said flexible portion having deformation properties adapted to allow the rigid portion of the tubular stem to be fit into said lateral service line at the angle at which the lateral service line is joined to the main pipeline; and,
sealing means interconnected to the exterior surface of said convex flange having resilient deformation properties adapted to provide sealing engagement between said convex flange and an interior surface of the main pipeline;
(b) determining a location of the junction between the main pipeline and the lateral service line;
(c) removably attaching said patch to a support cage;
(d) positioning said support cage adjacent to the location of the underground junction;
(e) activating a lateral extender to move said support cage from a first traveling position to a second engagement position so that said patch is positioned with said tubular stem within the lateral service line and said sealing substrate is positioned against an internal surface of the main pipeline proximate to said lateral service line;
(f) curing said patch so that said patch becomes fixedly connected to the internal surface of the main pipeline wherein said patch substantially prevents infiltration of foreign matter into the main pipeline at the underground junction;
(g) deactivating the lateral extender to move said support cage from the second engagement position to the first traveling position; and
(h) removing said lateral extender and said support cage from the main pipeline.
In another embodiment of the present invention, the following method is provided for installing a pipeline patch:
A method for remotely installing a patch to an underground junction between a main pipeline and a lateral service line, wherein said lateral service line is joined to the main pipeline at an angle other than a ninety-degree angle, comprising the steps of:
(a) providing a patch comprising:
a tubular stem having a substantially rigid portion, a flexible portion, a first end and a second end, the second end having a substantially open aperture for communication with the lateral service line;
a convex flange having an exterior service, an interior surface and a cutout portion operatively sized and interconnected to the first end of said tubular stem, wherein said tubular stem extends away from the exterior surface of said convex flange;
said flexible portion having deformation properties adapted to allow the rigid portion of the tubular stem to be fit into said lateral service line at the angle at which the lateral service line is joined to the main pipeline;
a seal, said seal adapted to fit within the aperture of the tubular stem to seal off the lateral service line; and,
sealing means interconnected to the exterior surface of said convex flange having resilient deformation properties adapted to provide sealing engagement between said convex flange and an interior surface of the main pipeline;
(b) determining a location of the junction between the main pipeline and the lateral service line;
(c) removably attaching said patch to a support cage;
(d) positioning said support cage adjacent to the location of the underground junction;
(e) activating a lateral extender to move said support cage from a first traveling position to a second engagement position so that said patch is positioned with said tubular stem within the lateral service line and said sealing substrate is positioned against an internal surface of the main pipeline proximate to said lateral service line;
(f) curing said patch so that said patch becomes fixedly connected to the internal surface of the main pipeline wherein said patch substantially prevents infiltration of foreign matter into the main pipeline at the underground junction;
(g) deactivating the lateral extender to move said support cage from the second engagement position to the first traveling position; and
(h) removing said lateral extender and said support cage from the main pipeline.
These and other objects, features, and advantages of the invention will become apparent from the following best mode description, the drawings and the claims.